Anaxagoras

Greek philosopher and scientist

• Born: c. 500 b.c.e.
• Birthplace: Clazomenae, Anatolia (now in Turkey)
• Died: c. 428 b.c.e.
• Place of death: Lampsacus (now Lapseki, Turkey)

By devising a philosophical system to explain the origins and nature of the physical universe that overcame the paradoxes and inconsistencies of earlier systems, Anaxagoras provided an indispensable bridge between the pre-Socratic philosophers of the archaic period of Greek history and the full flowering of philosophy during the Golden Age of Greece.

He grew to adulthood during the turbulent years of the wars of the Greek city-states against the Persian Empire. His own city, Clazomenae, forced to acknowledge the suzerainty of Darius the Great in 514, joined the Athenian-aided Ionian revolt against Persia in 498. That revolt ultimately was suppressed in 493. Anaxagoras’s childhood was spent during a time when the echoes of Athens’s great victory over Darius at Marathon in 490 were reverberating throughout the Hellenic world.

According to tradition, Anaxagoras became a resident of Athens in 480. That a young scholar should be attracted to the intellectual and artistic center of Greek civilization is not surprising, but it is doubtful that this change of residence took place in 480. Xerxes I chose that year to attempt to realize Darius’s dream of conquering the Greek polis. His plans were frustrated, and his great host scattered at the Battles of Salamis and Plataea during that same year. The next year, the Ionian cities of Asia Minor again rose in rebellion against Persia, and in 477 they joined with Athens in the Delian League. The League succeeded in expelling the Persians from the Greek states of Asia Minor. It seems more likely that the young Anaxagoras came to Athens after the alliance between the Ionian cities and the Athenians.

While in Athens, Anaxagoras became friends with the young Pericles and apparently influenced him considerably. Several classical scholars have concluded that Anaxagoras’s later trial was engineered by Pericles’ political rivals, in order to deprive Pericles of a trusted friend. Convicted of impiety after admitting that he thought the sun was a huge mass of “hot rock,” Anaxagoras went into exile at Lampsacus, where many young Greeks came to study with him before his death, probably in 428.

Life’s Work

Sometime in or shortly after 467, Anaxagoras published his only written work, apparently titled Nature. Of this work, only seventeen fragments totaling around twelve hundred words have survived, all recorded as quotations in the works of later generations of philosophers. That so few words could have inspired the more than fifty books and articles written about him in the twentieth century alone is ample testimony to Anaxagoras’s importance in the evolution of Greek philosophy and natural science.

Early Life

Virtually nothing is known of the parents of Anaxagoras (an-aks-AG-ur-uhs) or his childhood, adolescence, or education. Born into a wealthy family in an Ionian Greek city, he almost certainly was exposed to the attempts by Ionian philosophers, especially Parmenides, to explain the physical universe by postulating that everything is made from a single primordial substance. Anaxagoras apparently realized even before he was twenty years of age that such an assumption could not explain the phenomena of movement and change, and he began to devise a more satisfactory system.

Anaxagoras’s book was an ambitious attempt to explain the origins and nature of the universe without recourse (or so it seemed to many of his contemporaries) to any supernatural agents. Other Ionian philosophers, notably Parmenides, had preceded Anaxagoras in this endeavor, but their systems were logically unable to explain the multiplicity of “things” in the universe or to explain physical and biological change in those things because they had postulated that all things are made from the same basic “stuff.” Anaxagoras overcame the logical inconsistencies of this argument by postulating an infinite variety of substances that make up the whole of the universe. Anaxagoras argued that there is something of everything in everything. By this he meant that, for example, water contains a part of every other thing in the universe, from blood to rock to air. The reason that it is perceived to be water is that most of its parts are water. A hair also contains parts of every other thing, but most of its parts are hair.

In the beginning, according to the first fragment of Anaxagoras’s book, infinitely small parts of everything in equal proportions were together in a sort of primal soup. In fragment 3, he proposes a primitive version of the law of the conservation of energy, by saying that anything, no matter how small, can be divided infinitely, because it is not possible for something to become nonexistent through dividing. This idea of infinite divisibility is unique to the Anaxagorean system; no philosopher before or since has proposed it.

This universal mixture of all things acquired form and substance, according to fragment 12, through the actions of nous, or “mind.” Mind, Anaxagoras argues, is not part of everything (though it is a part of some things), nor is a part of everything found in mind (though parts of some things are found in mind). Mind set the primal soup into rotation, and the different things began to “separate off,” thus forming the universe. The rotation of the primal mixture not only separated everything according to its kind (but not perfectly, as everything still contains parts of every other thing) but also supplied heat, through friction. Among other things, friction ignited the sun and the stars. Considerable disagreement over the exact meaning Anaxagoras was trying to convey with the term “mind” has colored scholarly works on his book since Aristotle and continues to be a controversial issue.

Anaxagoras’s system not only enabled him and his students to describe all existing objects, but it also permitted the explanation of physical and biological change. It was the introduction of the idea of mind and its action as a formative agent in the creation of the universe for which Anaxagoras became famous and that rejuvenated Socrates’ interest and faith in philosophy.

Sometime after 467, Anaxagoras was accused of and tried for impiety (denying the gods) and “medism” (sympathizing with the Persians). The actual date of his trial and subsequent banishment from Athens is still hotly debated among classical scholars. The traditional date accepted by most historians is 450, but this seems unlikely for several reasons. By 450, the charge of medism could hardly have been a serious one, because the Persian Wars were long since over. Also, had he been in Athens in 450, the young Socrates would almost certainly have met him personally, but Socrates’ own words indicate that he knew Anaxagoras only through his book. Finally, Anaxagoras’s friend Pericles would have been fully able to protect his mentor from political opponents in 450. An earlier date for his exile from Athens seems likely. Some scholars have attempted to solve this problem by postulating that Anaxagoras visited Athens one or more times after being exiled shortly after the publication of his book. This seems the most reasonable explanation to reconcile the dispute, especially because several ancient sources place him in Athens as late as 437.

One of Anaxagoras’s most notable achievements during his stay in Athens was his postulation of the correct explanation for a solar eclipse. Anaxagoras was apparently the first to argue that an eclipse occurs when the moon (which he said was a large mass of cold rocks) passes between the earth and the sun (which he said was a larger mass of hot rocks). He may have reached this conclusion after the fall of a large meteorite near Aegypotomi in 467, which excited wide discussion throughout the Hellenic world.

After leaving Athens, Anaxagoras spent his remaining years as the head of a flourishing school at Lampsacus. How his philosophical system may have changed over the years between the publication of his book and the end of his life is unknown. He died at Lampsacus, probably in 428.

Significance

The thesis that Anaxagoras greatly influenced Socrates and Aristotle is easily proved by their elaborate discussions of his system in their own words. Through those two most influential of all Greek thinkers, he has had a profound impact on all subsequent generations of philosophers and natural scientists in the Western world. Some of Anaxagoras’s critics, both ancient and modern, accuse him of merely substituting the word “mind” for “God” or “the gods.” Thus, in their estimation, his philosophy becomes merely a humanistic religion. Other critics have dismissed Anaxagoras’s teachings as simplistic and unworthy of serious consideration. His supporters, from Aristotle to the present, have defended him as a pioneering thinker who provided much of the inspiration for the flowering of post-Socratic philosophy during the Golden Age of Greece and the Hellenistic world.

Early critics and supporters alike may have missed an important point in the Anaxagoras fragments. Modern scholarship on Anaxagoras points out that his concept of mind giving form to the universe is not far removed from the position of some modern physicists who argue that one’s perception of the universe is determined by one’s own senses, which provide an imperfect understanding at best. Anaxagoras may well have been trying to express this same concept (that without cognitive perception there is no form or substance to the universe) without possessing the technical language to do so.

Bibliography

Barnes, Jonathan. The Presocratic Philosophers. London: Routledge, 1993. Includes a chapter on Anaxagoras, reconstructing his philosophy from a careful examination of the fragments.

Davison, J. A. “Protagoras, Democritus, and Anaxagoras.” Classical Quarterly 3 (1953): 33-45. Establishes Anaxagoras’s position vis-à-vis other Greek philosophers and shows his influence on the “atomist” school that succeeded him. Also contains some information on his early life not available elsewhere in English and argues for an early date for his exile from Athens.

Gershenson, Daniel E., and Daniel A. Greenberg. Anaxagoras and the Birth of Physics. New York: Blaisdell, 1964. This controversial work suggests that the Anaxagoras fragments are not really the words of Anaxagoras, but rather his words as interpreted by later philosophers, notably Simplicius, who succeeded him. Contains a good, if somewhat theoretical, explanation of Anaxagoras’s system.

Guthrie, W. K. C. A History of Greek Philosophy. Vol. 2. Cambridge, England: Cambridge University Press, 1965. Contains the most complete account available of Anaxagoras’s life. Puts his life and teachings in the context of his times.

Kirk, Geoffrey S., John E. Raven, and M. Schofield. The Presocratic Philosophers. 2d ed. New York: Cambridge University Press, 1983. One chapter contains a scholarly account of Anaxagoras’s philosophy; includes Greek text of fragments.

Mansfield, J. “The Chronology of Anaxagoras’s Athenian Period and the Date of His Trial.” Mnemosyne 33 (1980): 17-95. Offers convincing arguments concerning Anaxagoras’s arrival in Athens, his trial, and his banishment. Also contains references to Anaxagoras’s relationship with Pericles and the political motives behind the former’s exile.

Mourelatos, Alexander P. D. The Pre-Socratics: A Collection of Critical Essays. Princeton, N.J.: Princeton University Press, 1993. Includes two essays by eminent scholars, Gregory Vlastos and G. B. Kerford, which attempt to reconstruct Anaxagoras’s philosophy in a way that makes it logically consistent. Both focus on his materialism.

Schofield, Malcolm. An Essay on Anaxagoras. Cambridge, England: Cambridge University Press, 1980. A clear, witty exposition of the philosophy of Anaxagoras and his importance in the history of philosophy. Perhaps the best work on Anaxagoras’s system and its meaning available in English.